Ecosystem

Do like this:

1. Clean the two plastic bottles properly.
2. Cut bottle No. 1 in half and put the top of the bottle away. It can be used for something else.
3. Pour clean sand into the bottom of the bottle and pour about 2 cm of water on top.
4. Cut about 3 cm off the bottom of bottle 2.
5. Take the upper part of the bottle and put it in the first bottle.
6. Pull a cotton string through it so that the string extends into the water.
7. Put in some soil and plant a plant or sow some seeds.
8. Take the bottom of the second bottle and turn upside down to put a lid on the ecosystem.
9. Study how the plants grow in the artificial ecosystem.

I give a thanks to lekolar.fi for the idea.